class Student{
    public String name;
    public String gender;
    public int age;
    public double score;
    public static int classroom = 1;
}
public class One {
    public static void main(String[] args) {
        Student student1 = new Student();
        Student student2 = new Student();
        Student student3 = new Student();
        student1.classroom++;
        student2.classroom++;
        student3.classroom--;
        Student.classroom++;
        System.out.println(Student.classroom);
    }
}
